1. Technical Field
The invention relates to energy conversion devices, and particularly to a photovoltaic device.
2. Description of Related Art
Currently, solar energy is considered a renewable and clean energy source, and can also be used as an alternative source of energy other than fossil fuel. Solar energy is generally produced by photovoltaic cells, also known as solar cells. The photovoltaic cell or the solar cell is a device that converts light into electrical energy using the photoelectric effect.
Generally, the solar cell includes a large-area p-n junction made from silicon. Silicon employed in the solar cell can be single crystal silicon or polycrystalline silicon. Referring to FIG. 5, a conventional solar cell 30 according to the prior art generally includes a silicon substrate 32, a doped silicon layer 34, a front electrode 36, and a rear electrode 38. The doped silicon layer 34 is formed in intimate contact with the silicon substrate 32 to form a p-n junction. The front electrode 36 is disposed on and electrically connected to the doped silicon layer 34. The rear electrode 38 is disposed on and electrically connected to, e.g. via ohmic contact, the silicon substrate 32. In use, the electrodes 36, 38 are connected to an external load. Current will be generated and flow in one direction across the p-n junction by the action of the electric field if light strikes the solar cell 30.
Generally, the electrodes 36, 38 are made of conductive metals, such as aluminum (Al), silver (Ag) or copper (Cu), which are usually not transparent to light. Therefore, the electrode 36, 38, in particular, the front electrode 36 is fabricated in a finger-shape or a comb-shape to increase amount of incoming light that can pass by the electrode. Moreover, in order to enhance photoelectric conversion efficiency, transparent conductive material, e.g. indium tin oxide (ITO), may instead be selected to form the front electrode 36. However, ITO material has drawbacks of, for example, being not chemically and mechanically durable, and having uneven distribution of resistance. As a result, the durability and the photoelectric conversion efficiency are relatively low for devices using transparent conductive materials.
What is needed, therefore, is a photovoltaic device that more efficient and durable is desired.
Corresponding reference characters indicate corresponding parts throughout the drawings. The exemplifications set out herein illustrate at least one embodiment of the present photovoltaic device, in one form, and such exemplifications are not to be construed as limiting the scope of the disclosure in any manner.